1. Field of the Invention
This invention relates to a method for producing acrylic coated polycarbonate articles; and, more particularly, relates to an improved method for providing protective, ultraviolet radiation cured coating on the surface of a polycarbonate substrate.
2. Description of Related Art
Polycarbonate films generally have acceptable levels of strength and clarity but lack high levels of abrasion resistance and chemical resistance. Radiation curable acrylic coatings and methods for their application to polycarbonate substrates are known, see for example European Patent 228,671 corresponding to European Patent Application 86 117,682. While prior methods exist for applying radiation curable acrylic coatings to polycarbonate film, the adhesion of these cured coatings to the underlying polycarbonate can be less than desirable.
Some prior radiation curable acrylic coating compositions have employed amounts of non-reactive solvents to reduce the viscosity of the coating compositions during application thereof to the polycarbonate substrate. These non-reactive volatile components have been eliminated from the coatings by employing a forced hot air drying system. The use of coating compositions containing substantial levels of non-reactive, volatile components such as solvents, for example more than 1 percent by weight based on the total weight of the composition is not desired because of environmental and safety concerns. Thus there is a need for a method for producing coated polycarbonate articles which involves applying radiation curable coatings substantially free of non-reactive volatile components to polycarbonate substrates to produce coated articles exhibiting good coating adhesion.
Accordingly one object of the present invention is to produce primerless coated polycarbonate articles having high levels of adhesion between the cured coating and the polycarbonate substrate while avoiding the use of non-reactive volatile components such as solvents.